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Wednesday, April 25, 2018

 

The Sky This Week - Thursday April 26 to Thursday May 3

The Full Moon is Monday, April 30.  Venus is high in the twilight and passes below the Hyades cluster and the bright star Aldebaran. Jupiter is now rising in the early evening skies and is visited by the Moon on the 30th. Venus is setting as Jupiter is rising. Mars and Saturn are now visible in the late evening skies. Mercury is prominent in the morning skies.

 The Full Moon is Monday, April 30.

Evening twilight sky on Thursday April 26 looking west as seen from Adelaide at 18:20 ACST (45 minutes after sunset). Venus is just above the Pleiades in the twilight, and below the Hyades. and the bright star Aldebaran. The inset shows the binocular view of Venus and the Pleiades.

Similar views will be seen throughout Australia at the equivalent local time (45 minutes after sunset, click to embiggen).

Venus is rising higher in the twilight. Venus is visible to the unaided eye from 15 minutes after sunset, easy to see 30 minutes after sunset and can potentially be viewed as late as an hour after sunset if you have a flat, unobstructed horizon.

Evening sky on Monday April 30 looking east  as seen from Adelaide at 19:05 ACST  (90 minutes after sunset). Jupiter is  above the horizon close to the full Moon.

The inset is a simulated telescopic view of Jupiter and its moons at 04:00 ACST on the 30th, with Ganymede and its shadow transiting the face of Jupiter.

Similar views will be seen throughout Australia at the equivalent local time (90 minutes after sunset, click to embiggen).

Evening sky on Saturday April 28 looking east  as seen from Adelaide at 23:00 ACST. Mars and Saturn are above the eastern horizon. The inset is a simulated telescopic view of Saturn and the globular cluster M22.


Similar views will be seen throughout Australia at the equivalent local time (90 minutes before sunrise).



Morning sky on Saturday April 28 looking east as seen from Adelaide at 5:45 ACST (60 minutes before sunrise). Mercury is the brightest object closest to the eastern horizon. The inset shows a simulated telescopic view of Mercury.


Similar views will be seen throughout Australia at the equivalent local time (60 minutes before sunrise).




 Venus  is now sufficiently high in the evening twilight to be readily visible above the horizon if there are not too many trees or buildings in the way. It is  now one and a half hand-spans above the horizon 30 minutes after sunset. It is bright enough to be visible 15 minutes after sunset and easy to see 30 minutes after sunset. Venus can potentially be viewed as late as an hour after sunset if you have a flat, unobstructed horizon.

Venus starts the week just above the beautiful cluster the Pleiades, but in the twilight glow you will need binoculars to see the Pleiades. As the week progresses Venus leaves the Pleiades behind and glides past the V shaped Hyades cluster and the bight red Star Aldebaran. Venus is closest to Aldebaran on Thursday May 3.



Mercury has returned to the morning sky, and now is in an excellent position for observation. Mercury is the brightest object above the eastern horizon. Mercury is now high enough for telescope observation. In even a small telescope the "half moon" shape of Mercury will be visible.

Jupiter  is rising in the early evening, and is now a good telescopic object in the late evening. There are some good Jovian Moon events this week. Jupiter is at opposition next week, and is in an excellent position for telescopic observation. Jupiter is rising as Venus is setting.

 Mars is in Sagittarius the archer and is now rising in the late evening. Mars is moving away from Saturn although the pair are still obvious together.   Mars is brightening ahead of opposition later this year.

Saturn has entered the evening sky, although telescopically it is still best in the morning sky. It is within binocular range of several attractive clusters and nebula. It is close to the bright globular cluster M22 and the pair are visible in binoculars and wide field telescope eyepieces.

Printable PDF maps of the Eastern sky at 10 pm AEST, Western sky at 10 pm AEST. For further details and more information on what's up in the sky, see Southern Skywatch.
Cloud cover predictions can be found at SkippySky.

Here is the near-real time satellite view of the clouds (day and night) http://satview.bom.gov.au/

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Saturday, April 21, 2018

 

[Aurora Alert] Geomagnetic warning and Aurora Watch (21 April)

The SWS has issued a geomagnetic warning and aurora watch for 21 April (UT) due to ongoing solar wind streams from a coronal hole. This can be anytime the UT day on the 21st.  The SWS predicts active conditions with the possibility of outbreaks of minor storms. 

If these geomagnetic events occur and result in aurora they could be seen from Tasmania weather permitting. The Moon is waxing and will not interfere with aurora. Be patient, as the activity may rise and fall of the magnetic polarity of the wind may fluctuate significantly.




Current condition are not yet conductive to aurora.

This event is unlikely to be spectacular, but still worth a look as viewing conditions are good.

Dark sky sites have the best chance of seeing anything, and always allow around 5 minutes for your eyes to become dark adapted.

As always look to the south for shifting red/green glows, beams have been reported consistently over the last few aurora, as well as bright proton arcs and "picket fences". A double arc,  blobs, and curtains were seen in Septembers aurora  last despite the moonlight.

Here is the near-real time satellite view of the clouds http://satview.bom.gov.au/
Cloud cover predictions can be found at SkippySky.  

A new aurora camera is being installed at Campania, Tasmania. A live feed of the images from this camera is still not available.

SUBJ: SWS GEOMAGNETIC DISTURBANCE WARNING 18/08
ISSUED AT 0631UT/20 APRIL 2018
BY THE AUSTRALIAN SPACE FORECAST CENTRE.

Earth is currently under the influence of a high speed stream
from a negative polarity equatorial coronal hole. Geomagnetic
activity at Quiet to Active levels is expected and at times may
reach up to Minor Storm levels if there are notable southward
Bz periods.

INCREASED GEOMAGNETIC ACTIVITY EXPECTED
DUE TO CORONAL HOLE HIGH SPEED WIND STREAM
FROM 20-21 APRIL 2018
_____________________________________________________________

GEOMAGNETIC ACTIVITY FORECAST
20 Apr:  Quiet to Active
21 Apr:  Quiet to Active

_____________________________________________________________
SUBJ: SWS AURORA WATCH
ISSUED AT 0117 UT ON 21 Apr 2018 by Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE

The solar wind is currently under the influence of a high speed solar
wind stream from a recurrent coronal hole. Geomagnetic activity
reached storm levels on April 20 and is forecast to be at unsettled to
active levels on April 21, with possible isolated minor storm periods.
If significant geomagnetic activity occurs, there will be a chance of
visible auroras for southernmost Australian regions (e.g., Tasmania
and coastline of Victoria) during local nighttime hours. Aurora alerts
will follow if significant geomagnetic activity actually occurs. Visit
the SWS Aurora webpage http://www.sws.bom.gov.au/Aurora for current
aurora viewing conditions.


Our Aurora forecasting tool, located at
http://www.sws.bom.gov.au/Aurora/3/1, may help to estimate regions
from where aurora would be visible.

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Wednesday, April 18, 2018

 

Venus and the Crescent Moon, Wednesday 18 April.

Venus and the crescent Moon on Wednesday 18 April, looking west at 18:21 ACST. Canon IXUS, 3xzoom, 1 sec exposure ASA 400. Click to embiggen.Image taken with my mobile phone almost immediately after, no idea of the conditions. Resolution is less than the canon shot. Click to embiggen.

After cloud and rain wiping out the Moon-Venus conjunction on the 17th, conditions tonight were good enough that I got the closer pairing of Venus and the Moon. The clouds made Venus a bit hard to see, but the twiligh glow made the whole scene rather spectacular.

Tomorrow will have the Moon further away from Venus but close to Aldebaran, which should look nice as well.

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The 2018 Australian Lyrid Meteor Shower, Morning 23 April

The morning sky looking north as seen from Brisbane at 5:00 am AEST on April 23. The Lyrid radiant is marked with a starburst. It is quite close to the obvious bright star Vega low above the northern horizon.

Similar views will be seen elsewhere at an equivalent local time. The radiant will be higher in northern Australia, and lower in southern Australia (click to embiggen). 

The Lyrids, the debris of comet C/1861 G1 (Thatcher) are a weak but reliable shower that occurs every year between April 16- April 25, with the peak this year on April 23 Australian time.

That's  around 10 am 23 April in east coast Australia, the radiant doesn't rise until 1 am on the 23rd, so the best time to view the Lyrids in Australia is from 4 am on the 23rd. 

The predicted ZHR this year is 18 meteors per hour. the number of meteors you could expect to see if the radiant (the apparent position where the meteors originate) was at the highest point of the sky, under dark sky conditions. Under ideal conditions, you will see a meteor on average about once every three minutes. This can be as interesting as watching paint dry. Also, while that meteor every three minutes is the average, meteors are like buses, you wait for ages and then a whole bunch turn up. In Australia, the rate is much less.

Under real conditions the Lyrids radiant will not rise to the zenith from most places, and most places won't have really dark skies. The lower the radiant is, the thicker atmosphere will obscure the fainter meteors, and some of the meteors will start to "burn" below the horizon, so over all you will see fewer.

This is particularly true in Australia, where the radiant is very low to the northern horizon. In Australia the radiant rises about 1 am local time, but it is not really high enough for there to be any real chance of seeing meteors until around 4 am, when the radiant is between three hand-spans to four hand-spans above the horizon (see diagram above). The Moon has long set, so Moonlight is not a factor this year.

From Australia, at 4 am, under dark sky conditions, we will see between 4 meteors per hour (southern states) to 6-8 meteors per hour (Northern Territory and QLD).


 If you want to see what the rates will be like at your area, try the Meteor Flux Estimator. The illustration shows the output for dark sky sites in Brisbane.

Unfortunately, both Chrome and Firefox have changed their security settings to prevent plugins from running, and the flux estimator only runs under Internet Explorer now.

Choose 6 April Lyrids from the drop down meteor shower Menu, the date (make sure that you set the year to 2015, and your location, most people will have to put in their latitude and longitude (strangely, Adelaide, Brisbane, Darwin and Perth are listed in the drop down menu, but Sydney, Melbourne and Hobart are not) under "other" in the location box.



This will give you a chart of the numbers of meteors per hour you can expect at various times (see image to the left).

The Lyrids are pretty poor in Australia, but if you are patient you may see the occasional meteor shooting up from below the horizon.

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Tuesday, April 17, 2018

 

The Sky This Week - Thursday April 19 to Thursday April 26

The First Quarter Moon is Monday, April 23.  Venus is low in the twilight and is visited by the Moon on the 19th. Jupiter is now rising in the early evening skies. Mars and Saturn are now visible in the late evening skies. Mercury is prominent in the morning skies. The Lyrid meteor shower peaks on the morning of the 23rd, but is really only visible form Brisbane and places north.

The First Quarter Moon is Monday, April 23. The  Moon is at perigee, when it is closest to the Earth, on the 21st.


Evening twilight sky on Thursday April 19 looking west as seen from Adelaide at 18:14 ACST (30 minutes after sunset). Venus is just above the horizon in the twilight. The crescent Moon is above it close to the bright star Aldebaran.

Similar views will be seen throughout Australia at the equivalent local time (30 minutes after sunset, click to embiggen).

Venus is rising higher in the twilight. While is is now much easier to see, you will still need a flat unobscured horizon to see it at its best. Venus is visible to the unaided eye from 15 minutes after sunset, easy to see 30 minutes after sunset and can potentially be viewed as late as an hour after sunset if you have a flat, unobstructed horizon.

Evening sky on Saturday April 21 looking east  as seen from Adelaide at 23:00ACST. Jupiter is  high above the horizon. Saturn is close to the horizon and Mars is just rising.

The inset is a simulated telescopic view of Jupiter and its moons at 3:00 ACST on the 22nd, with Europa and its shadow transiting the face of Jupiter.

Similar views will be seen throughout Australia at the equivalent local time (click to embiggen).


Morning sky on Saturday April 21 looking north as seen from Adelaide at 5:19 ACST (90 minutes before sunrise). Mars and Saturn are high above the northern horizon and good telescopic viewing. The inset is a simulated telescopic view of Saturn and the globular cluster M22.


Similar views will be seen throughout Australia at the equivalent local time (90 minutes before sunrise).



Morning sky on Saturday April 21 looking east as seen from Adelaide at 5:45 ACST (60 minutes before sunrise). Mercury is the brightest object closest to the eastern horizon.











The morning sky looking north as seen from Brisbane at 5:00 am AEST on April 23. The Lyrid radiant is marked with a yellow cross. Similar views will be seen elsewhere at an equivalent local time. The radiant will be higher in northern Australia, and lower in southern Australia (click to embiggen).  
 
The predicted ZHR this year is 18 meteors per hour. This means that under ideal conditions, you will see a meteor on average about once every three minutes. This can be as interesting as watching paint dry. Also, while that meteor every three minutes is the average, meteors are like buses, you wait for ages and then a whole bunch turn up.  But alos, that is under ideal conditions. In Australia, where the radiant is very low above the horizon, you are likely to see a meteor once every 10 minutes from the latitudes of Brisbane, far fewer to the south of this, with the best rates seen from Cairns and Darwin.

Venus  is now sufficiently high in the evening twilight to be readily visible above the horizon if there are not too many trees or buildings in the way. It is  now over a hand-span above the horizon 30 minutes after sunset. It is bright enough to be visible 15 minutes after sunset and easy to see 30 minutes after sunset and can potentially be viewed as late as an hour after sunset if you have a flat, unobstructed horizon. On the 19th the thin crescent Moon is near Venus.

Mercury has returned to the morning sky, and now is in an excellent position for observation. Mercury is the brightest object closest to the eastern horizon.


Jupiter  is rising in the early evening, and is now a good telescopic object in the late evening. There are some good Jovian Moon events this week.

 Mars is in Sagittarius the archer and is now rising in the late evening. Mars is moving away from Saturn although the pair are still obvious together.   Mars is brightening ahead of opposition later this year.

Saturn has entered the evening sky, although telescopically it is still best in the morning sky. It is within binocular range of several attractive clusters and nebula. It is close to the bright globular cluster M22 and the pair are visible in binoculars and wide field telescope eyepieces.

Printable PDF maps of the Eastern sky at 10 pm AEST, Western sky at 10 pm AEST. For further details and more information on what's up in the sky, see Southern Skywatch.
Cloud cover predictions can be found at SkippySky.

Here is the near-real time satellite view of the clouds (day and night) http://satview.bom.gov.au/

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Tuesday, April 10, 2018

 

The Sky This Week - Thursday April 12 to Thursday April 19

The New Moon is Monday, April 16.  Venus is low in the twilight and is visited by the Moon on the 19th. Jupiter is now rising in the early evening skies. Mars and Saturn are now visible in the late evening skies. Mercury returns to the morning skies.

The New Moon is Monday, April 16.

Evening twilight sky on Thursday April 19 looking west as seen from Adelaide at 18:14 ACST (30 minutes after sunset). Venus is just above the horizon in the twilight. The crescent Moon is above it close to the bright star Aldebaran.

Similar views will be seen throughout Australia at the equivalent local time (30 minutes after sunset, click to embiggen).

Venus is rising higher in the twilight. While is is now much easier to see, you will still need a flat unobscured horizon to see it at its best. Venus is now visible to the unaided eye from 15 minutes after sunset and easy to see 30 minutes after sunset and can potentially be viewed as late as an hour after sunset if you have a flat, unobstructed horizon.

Evening sky on Saturday April 14 looking east  as seen from Adelaide at 23:00ACST. Jupiter is  high above the horizon. Close to the horizon Saturn is just rising, and Mars will soon follow.

The inset is a simulated telescopic view of Jupiter and its moons at 1:30 ACST on the 15th, with Ganymede and its shadow transiting the face of Jupiter.

Similar views will be seen throughout Australia at the equivalent local time (click to embiggen).



Morning sky on Saturday April 14 looking north as seen from Adelaide at 5:14 ACST (90 minutes before sunrise). Mars and Saturn are high above the northern horizon and good telescopic viewing.


Similar views will be seen throughout Australia at the equivalent local time (90 minutes before sunrise).



Venus  is now sufficiently high in the evening twilight to be readily visible above the horizon if there are not too many trees or buildings in the way. It is  now over a hand-span above the horizon 30 minutes after sunset. It is bright enough to be visible 15 minutes after sunset and easy to see 30 minutes after sunset and can potentially be viewed as late as an hour after sunset if you have a flat, unobstructed horizon.

Mercury has returned to the morning sky, but will be difficult to see until next week.

Jupiter  is rising in the early evening, and is now a good telescopic object in the late evening. There are some good Jovian Moon events this week.

 Mars is in Sagittarius the archer and is now rising in the late evening. Mars is moving away from Saturn although the pair are still obvious together.   Mars is brightening ahead of opposition later this year.

Saturn has entered the evening sky, although telescopically it is still best in the morning sky. It is within binocular range of several attractive clusters and nebula. It is close to the bright globular cluster M22 and the pair are visible in binoculars and wide field telescope eyepieces. Saturn is at aphelion on the 17th and appears motionless against the background stars.

Printable PDF maps of the Eastern sky at 10 pm AEST, Western sky at 10 pm AEST. For further details and more information on what's up in the sky, see Southern Skywatch.
Cloud cover predictions can be found at SkippySky.

Here is the near-real time satellite view of the clouds (day and night) http://satview.bom.gov.au/
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Tuesday, April 03, 2018

 

The Sky This Week - Thursday April 5 to Thursday April 12

The Last Quarter Moon is Sunday, April 8.  Venus is low in the twilight. Jupiter is now rising in the early evening skies. The waning Moon visits Saturn and Mars on April the 7thrd. Mars, bright Jupiter and Saturn form a line together with the bright stars Antares and Spica in the morning skies. Mars and Saturn are now visible in the late evening skies.

The Last Quarter Moon is Sunday, April 8. The Moon is at apogee, when it is furthest from the Earth, on the 8th.

Evening twilight sky on Saturday April 7 looking west as seen from Adelaide at 18:27 ACST (30 minutes after sunset). Venus is just above the horizon in the twilight.

Similar views will be seen throughout Australia at the equivalent local time (30 minutes after sunset, click to embiggen).

Venus is rising higher in the twilight. While is is now much easier to see, you will still need a flat unobscured horizon to see it at its best. Venus is now visible to the unaided eye from 15 minutes after sunset and easy to see 30 minutes after sunset.

Evening sky on Saturday April 7 looking east  as seen from Adelaide at 23:59 ACST. Jupiter is  high above the horizon. Close to the horizon is the triangle of Saturn Mars and the Last Quarter Moon.

The inset is a simulated telescopic view of Jupiter and its moons at 23:00 ACST, with Ganymede and its shadow transiting the face of Jupiter.

Similar views will be seen throughout Australia at the equivalent local time (click to embiggen).



Morning sky on Sunday April 8 looking north as seen from Adelaide at 5:09 ACST (90 minutes before sunrise). Mars, Saturn and the Last Quarter Moon form a triangle. The inset shows the binocular view of Mars, Saturn and the Moon. Because of the closeness of the bright Moon the faint deep-sky objects will be difficult to see.


Similar views will be seen throughout Australia at the equivalent local time (90 minutes before sunrise).


Venus  is now sufficiently high in the evening twilight to be readily visible above the horizon if there are not too many trees or buildings in the way. It is  now over a hand-span above the horizon 30 minutes after sunset. It is bright enough to be visible 15 minutes after sunset.

Mercury is lost to view.

Jupiter  is rising in the early evening, and is now a good telescopic object in the late evening. There are some good Jovian Moon events this week.

 Mars is in Sagittarius the archer and is now rising in the late evening. Mars is away from Saturn and the globular cluster M22.   Mars and Saturn and M22 start the week within binocular range of each other. On the evening of the 7th and the morning of the 8th the Last Quarter Moon is close to Saturn and Mars, forming a triangle. The proximity of the Moon makes viewing the fain deep sky objects difficult.

Saturn has entered the evening sky, although telescopically it is still best in the morning sky. It is within binocular range of several attractive clusters and nebula. It is close to the  bright globular cluster M22 and the pair are visible in binoculars and wide field telescope eyepieces. Mars and Saturn are within binocular range of each other. On the evening of the 7th and the morning of the 8th the Last Quarter Moon iis close to Saturn and Mars, forming a triangle. The proximity of the Moon makes viewing the fain deep sky objects difficult.

Printable PDF maps of the Eastern sky at 10 pm AEST, Western sky at 10 pm AEST. For further details and more information on what's up in the sky, see Southern Skywatch.
Cloud cover predictions can be found at SkippySky.

Here is the near-real time satellite view of the clouds (day and night) http://satview.bom.gov.au/
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